MainService+Activity+cpp: Implemented configurable address binding

When applied, this commit tries to implement the feature requests reported on issue bk138#43 and bk138#227.
Basically, with this commit, it is possible to instruct the server to listen only on a certain address.

To do this, there is a further edittext "Listening Address", which can be configured.
Please note that if an invalid ip/address is set, by default, it is assumed 0.0.0.0 is requested

app/src/main/cpp/droidvnc-ng.c

@@ -288,7 +288,7 @@ JNIEXPORT jboolean JNICALL Java_net_christianbeier_droidvnc_1ng_MainService_vncS
 }
 
 
-JNIEXPORT jboolean JNICALL Java_net_christianbeier_droidvnc_1ng_MainService_vncStartServer(JNIEnv *env, jobject thiz, jint width, jint height, jint port, jstring desktopname, jstring password, jstring httpRootDir) {
+JNIEXPORT jboolean JNICALL Java_net_christianbeier_droidvnc_1ng_MainService_vncStartServer(JNIEnv *env, jobject thiz, jint width, jint height, jstring host, jint port, jstring desktopname, jstring password, jstring httpRootDir) {
 
     int argc = 0;
 
@@ -315,6 +315,17 @@ JNIEXPORT jboolean JNICALL Java_net_christianbeier_droidvnc_1ng_MainService_vncS
     theScreen->setXCutTextUTF8 = onCutText;
     theScreen->newClientHook = onClientConnected;
 
+    in_addr_t address = 0; // Default is 0.0.0.0 (all available interfaces)
+    if (host != NULL) {
+        const char *hostNative = (*env)->GetStringUTFChars(env, host, NULL);
+        if (!rfbStringToAddr((char*)hostNative, &address)) {
+            address = 0; // Assign 0.0.0.0 (any) in case of errors
+        }
+        (*env)->ReleaseStringUTFChars(env, host, hostNative);
+    }
+
+    // With listenInterface one can define where the server will be available
+    theScreen->listenInterface = address;
     theScreen->port = port;
     theScreen->ipv6port = port;
 
@@ -491,4 +502,12 @@ JNIEXPORT jint JNICALL Java_net_christianbeier_droidvnc_1ng_MainService_vncGetFr
 
 JNIEXPORT jboolean JNICALL Java_net_christianbeier_droidvnc_1ng_MainService_vncIsActive(JNIEnv *env, jobject thiz) {
     return theScreen && rfbIsActive(theScreen);
+}
+
+JNIEXPORT jint JNICALL Java_net_christianbeier_droidvnc_1ng_MainService_vncGetListenInterface(JNIEnv *env, jobject thiz) {
+    if (!theScreen) {
+        return -1;
+    }
+
+    return theScreen->listenInterface;
 }

app/src/main/java/net/christianbeier/droidvnc_ng/Constants.java

@@ -25,6 +25,7 @@ public class Constants {
     /*
         user settings
      */
+    public static final String PREFS_KEY_SETTINGS_LISTEN_INTERFACE = "settings_listen_interface";
     public static final String PREFS_KEY_SETTINGS_PORT = "settings_port";
     public static final String PREFS_KEY_SETTINGS_PASSWORD = "settings_password" ;
     public static final String PREFS_KEY_SETTINGS_START_ON_BOOT = "settings_start_on_boot" ;

app/src/main/java/net/christianbeier/droidvnc_ng/Defaults.kt

@@ -40,6 +40,10 @@ class Defaults {
         private const val PREFS_KEY_DEFAULTS_ACCESS_KEY = "defaults_access_key"
     }
 
+    @EncodeDefault
+    var listenInterface = "0.0.0.0"
+        private set
+
     @EncodeDefault
     var port = 5900
         private set
@@ -116,6 +120,7 @@ class Defaults {
         try {
             val jsonString = jsonFile.readText()
             val readDefault = Json.decodeFromString<Defaults>(jsonString)
+            this.listenInterface = readDefault.listenInterface
             this.port = readDefault.port
             this.portReverse = readDefault.portReverse
             this.portRepeater = readDefault.portRepeater

app/src/main/java/net/christianbeier/droidvnc_ng/MainActivity.java

@@ -103,6 +103,7 @@ protected void onCreate(Bundle savedInstanceState) {
         mButtonToggle.setOnClickListener(view -> {
 
             Intent intent = new Intent(MainActivity.this, MainService.class);
+            intent.putExtra(MainService.EXTRA_LISTEN_INTERFACE, prefs.getString(Constants.PREFS_KEY_SETTINGS_LISTEN_INTERFACE, mDefaults.getListenInterface()));
             intent.putExtra(MainService.EXTRA_PORT, prefs.getInt(Constants.PREFS_KEY_SETTINGS_PORT, mDefaults.getPort()));
             intent.putExtra(MainService.EXTRA_PASSWORD, prefs.getString(Constants.PREFS_KEY_SETTINGS_PASSWORD, mDefaults.getPassword()));
             intent.putExtra(MainService.EXTRA_FILE_TRANSFER, prefs.getBoolean(Constants.PREFS_KEY_SETTINGS_FILE_TRANSFER, mDefaults.getFileTransfer()));
@@ -306,6 +307,35 @@ protected void onCreate(Bundle savedInstanceState) {
         });
 
 
+        final EditText listenInterface = findViewById(R.id.settings_listen_interface);
+        listenInterface.setText(prefs.getString(Constants.PREFS_KEY_SETTINGS_LISTEN_INTERFACE, mDefaults.getListenInterface()));
+        listenInterface.addTextChangedListener(new TextWatcher() {
+            @Override
+            public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
+
+            }
+
+            @Override
+            public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
+                // only save new value if it differs from the default and was not saved before
+                if(!(prefs.getString(Constants.PREFS_KEY_SETTINGS_LISTEN_INTERFACE, null) == null && charSequence.toString().equals(mDefaults.getListenInterface()))) {
+                    SharedPreferences.Editor ed = prefs.edit();
+                    ed.putString(Constants.PREFS_KEY_SETTINGS_LISTEN_INTERFACE, charSequence.toString());
+                    ed.apply();
+                }
+            }
+
+            @Override
+            public void afterTextChanged(Editable editable) {
+
+            }
+        });
+        listenInterface.setOnFocusChangeListener((v, hasFocus) -> {
+            // move cursor to end of text
+            listenInterface.setSelection(listenInterface.getText().length());
+        });
+
+
         final EditText port = findViewById(R.id.settings_port);
         if(prefs.getInt(Constants.PREFS_KEY_SETTINGS_PORT, mDefaults.getPort()) < 0) {
             port.setHint(R.string.main_activity_settings_port_not_listening);
@@ -757,7 +787,15 @@ private void onServerStarted() {
         if(MainService.getPort() >= 0) {
             HashMap<ClickableSpan, Pair<Integer,Integer>> spans = new HashMap<>();
             // uhh there must be a nice functional way for this
-            ArrayList<String> hosts = MainService.getIPv4s();
+            ArrayList<String> hosts = null;
+
+            if (MainService.isListeningOnAnyInterface()) {
+                hosts = MainService.getIPv4s();
+            } else {
+                hosts = new ArrayList<>();
+                hosts.add(MainService.getListenInterface());
+            }
+
             StringBuilder sb = new StringBuilder();
             sb.append(getString(R.string.main_activity_address)).append(" ");
             for (int i = 0; i < hosts.size(); ++i) {
@@ -768,10 +806,13 @@ private void onServerStarted() {
                 ClickableSpan clickableSpan = new ClickableSpan() {
                     @Override
                     public void onClick(@NonNull View widget) {
+                        final int usedPort = MainService.getPort();
+                        final int usedHttpPort = usedPort - 100;
+
                         Intent sendIntent = new Intent();
                         sendIntent.setAction(Intent.ACTION_SEND);
                         sendIntent.putExtra(Intent.EXTRA_TEXT,
-                                "http://" + host + ":5800/vnc.html?autoconnect=true&show_dot=true&&host=" + host + "&port=" + MainService.getPort());
+                                "http://" + host + ":" + usedHttpPort + "/vnc.html?autoconnect=true&show_dot=true&&host=" + host + "&port=" + usedPort);
                         sendIntent.setType("text/plain");
                         startActivity(Intent.createChooser(sendIntent, null));
                     }
@@ -798,6 +839,7 @@ public void onClick(@NonNull View widget) {
         findViewById(R.id.outbound_buttons).setVisibility(View.VISIBLE);
 
         // indicate that changing these settings does not have an effect when the server is running
+        findViewById(R.id.settings_listen_interface).setEnabled(false);
         findViewById(R.id.settings_port).setEnabled(false);
         findViewById(R.id.settings_password).setEnabled(false);
         findViewById(R.id.settings_access_key).setEnabled(false);
@@ -823,6 +865,7 @@ private void onServerStopped() {
         findViewById(R.id.outbound_buttons).setVisibility(View.GONE);
 
         // indicate that changing these settings does have an effect when the server is stopped
+        findViewById(R.id.settings_listen_interface).setEnabled(true);
         findViewById(R.id.settings_port).setEnabled(true);
         findViewById(R.id.settings_password).setEnabled(true);
         findViewById(R.id.settings_access_key).setEnabled(true);

app/src/main/java/net/christianbeier/droidvnc_ng/MainService.java

@@ -73,6 +73,7 @@ public class MainService extends Service {
     public static final String ACTION_CONNECT_REPEATER = "net.christianbeier.droidvnc_ng.ACTION_CONNECT_REPEATER";
     public static final String EXTRA_REQUEST_ID = "net.christianbeier.droidvnc_ng.EXTRA_REQUEST_ID";
     public static final String EXTRA_REQUEST_SUCCESS = "net.christianbeier.droidvnc_ng.EXTRA_REQUEST_SUCCESS";
+    public static final String EXTRA_LISTEN_INTERFACE = "net.christianbeier.droidvnc_ng.EXTRA_LISTEN_INTERFACE";
     public static final String EXTRA_HOST = "net.christianbeier.droidvnc_ng.EXTRA_HOST";
     public static final String EXTRA_PORT = "net.christianbeier.droidvnc_ng.EXTRA_PORT";
     public static final String EXTRA_REPEATER_ID = "net.christianbeier.droidvnc_ng.EXTRA_REPEATER_ID";
@@ -104,6 +105,8 @@ public class MainService extends Service {
 
     final static String ACTION_HANDLE_NOTIFICATION_RESULT = "action_handle_notification_result";
 
+    private static final String PREFS_KEY_SERVER_LAST_LISTEN_INTERFACE_WILDCARD = "server_last_listen_interface_wildcard" ;
+    private static final String PREFS_KEY_SERVER_LAST_LISTEN_INTERFACE = "server_last_listen_interface" ;
     private static final String PREFS_KEY_SERVER_LAST_PORT = "server_last_port" ;
     private static final String PREFS_KEY_SERVER_LAST_PASSWORD = "server_last_password" ;
     private static final String PREFS_KEY_SERVER_LAST_FILE_TRANSFER = "server_last_file_transfer" ;
@@ -166,9 +169,10 @@ public void onServiceUnregistered(NsdServiceInfo nsdServiceInfo) {
     }
 
     @SuppressWarnings("BooleanMethodIsAlwaysInverted")
-    private native boolean vncStartServer(int width, int height, int port, String desktopName, String password, String httpRootDir);
+    private native boolean vncStartServer(int width, int height, String host, int port, String desktopName, String password, String httpRootDir);
     private native boolean vncStopServer();
     private native boolean vncIsActive();
+    private native int vncGetListenInterface();
     private native long vncConnectReverse(String host, int port);
     private native long vncConnectRepeater(String host, int port, String repeaterIdentifier);
     static native boolean vncNewFramebuffer(int width, int height);
@@ -331,16 +335,24 @@ public int onStartCommand(Intent intent, int flags, int startId)
                 startScreenCapture();
             } else {
                 DisplayMetrics displayMetrics = Utils.getDisplayMetrics(this, Display.DEFAULT_DISPLAY);
+                String listenInterface = PreferenceManager.getDefaultSharedPreferences(this).getString(PREFS_KEY_SERVER_LAST_LISTEN_INTERFACE, mDefaults.getListenInterface()).toLowerCase();
                 int port = PreferenceManager.getDefaultSharedPreferences(this).getInt(PREFS_KEY_SERVER_LAST_PORT, mDefaults.getPort());
                 // get device name
                 String name = Utils.getDeviceName(this);
 
                 boolean status = vncStartServer(displayMetrics.widthPixels,
                         displayMetrics.heightPixels,
+                        listenInterface,
                         port,
                         name,
                         PreferenceManager.getDefaultSharedPreferences(this).getString(PREFS_KEY_SERVER_LAST_PASSWORD, mDefaults.getPassword()),
                         getFilesDir().getAbsolutePath() + File.separator + "novnc");
+
+                final SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
+                SharedPreferences.Editor ed = prefs.edit();
+                ed.putBoolean(PREFS_KEY_SERVER_LAST_LISTEN_INTERFACE_WILDCARD, this.vncGetListenInterface() == 0);
+                ed.apply();
+
                 Intent answer = new Intent(ACTION_START);
                 answer.putExtra(EXTRA_REQUEST_ID, PreferenceManager.getDefaultSharedPreferences(this).getString(PREFS_KEY_SERVER_LAST_START_REQUEST_ID, null));
                 answer.putExtra(EXTRA_REQUEST_SUCCESS, status);
@@ -374,15 +386,22 @@ public int onStartCommand(Intent intent, int flags, int startId)
             if (mResultCode != 0 && mResultData != null
                     || (Build.VERSION.SDK_INT >= 30 && PreferenceManager.getDefaultSharedPreferences(this).getBoolean(PREFS_KEY_SERVER_LAST_FALLBACK_SCREEN_CAPTURE, false))) {
                 DisplayMetrics displayMetrics = Utils.getDisplayMetrics(this, Display.DEFAULT_DISPLAY);
+                String listenInterface = PreferenceManager.getDefaultSharedPreferences(this).getString(PREFS_KEY_SERVER_LAST_LISTEN_INTERFACE, mDefaults.getListenInterface()).toLowerCase();
                 int port = PreferenceManager.getDefaultSharedPreferences(this).getInt(PREFS_KEY_SERVER_LAST_PORT, mDefaults.getPort());
                 String name = Utils.getDeviceName(this);
                 boolean status = vncStartServer(displayMetrics.widthPixels,
                         displayMetrics.heightPixels,
+                        listenInterface,
                         port,
                         name,
                         PreferenceManager.getDefaultSharedPreferences(this).getString(PREFS_KEY_SERVER_LAST_PASSWORD, mDefaults.getPassword()),
                         getFilesDir().getAbsolutePath() + File.separator + "novnc");
 
+                final SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
+                SharedPreferences.Editor ed = prefs.edit();
+                ed.putBoolean(PREFS_KEY_SERVER_LAST_LISTEN_INTERFACE_WILDCARD, this.vncGetListenInterface() == 0);
+                ed.apply();
+
                 Intent answer = new Intent(ACTION_START);
                 answer.putExtra(EXTRA_REQUEST_ID, PreferenceManager.getDefaultSharedPreferences(this).getString(PREFS_KEY_SERVER_LAST_START_REQUEST_ID, null));
                 answer.putExtra(EXTRA_REQUEST_SUCCESS, status);
@@ -445,6 +464,8 @@ public int onStartCommand(Intent intent, int flags, int startId)
             // Step 0: persist given arguments to be able to recover from possible crash later
             final SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
             SharedPreferences.Editor ed = prefs.edit();
+
+            ed.putString(PREFS_KEY_SERVER_LAST_LISTEN_INTERFACE, intent.getStringExtra(EXTRA_LISTEN_INTERFACE) != null ? intent.getStringExtra(EXTRA_LISTEN_INTERFACE) : prefs.getString(Constants.PREFS_KEY_SETTINGS_LISTEN_INTERFACE, mDefaults.getListenInterface()));
             ed.putInt(PREFS_KEY_SERVER_LAST_PORT, intent.getIntExtra(EXTRA_PORT, prefs.getInt(Constants.PREFS_KEY_SETTINGS_PORT, mDefaults.getPort())));
             ed.putString(PREFS_KEY_SERVER_LAST_PASSWORD, intent.getStringExtra(EXTRA_PASSWORD) != null ? intent.getStringExtra(EXTRA_PASSWORD) : prefs.getString(Constants.PREFS_KEY_SETTINGS_PASSWORD, mDefaults.getPassword()));
             ed.putBoolean(PREFS_KEY_SERVER_LAST_FILE_TRANSFER, intent.getBooleanExtra(EXTRA_FILE_TRANSFER, prefs.getBoolean(Constants.PREFS_KEY_SETTINGS_FILE_TRANSFER, mDefaults.getFileTransfer())));
@@ -793,6 +814,25 @@ static ArrayList<String> getIPv4s() {
         return hosts;
     }
 
+
+    static boolean isListeningOnAnyInterface() {
+        try {
+            SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(instance);
+            return prefs.getBoolean(PREFS_KEY_SERVER_LAST_LISTEN_INTERFACE_WILDCARD, false);
+        } catch (Exception e) {
+            return false;
+        }
+    }
+
+    static String getListenInterface() {
+        try {
+            SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(instance);
+            return prefs.getString(PREFS_KEY_SERVER_LAST_LISTEN_INTERFACE, new Defaults(instance).getListenInterface());
+        } catch (Exception e) {
+            return null;
+        }
+    }
+
     static int getPort() {
         try {
             SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(instance);

app/src/main/java/net/christianbeier/droidvnc_ng/OnBootReceiver.java

@@ -54,6 +54,7 @@ public void onReceive(Context context, Intent arg1)
 
             Intent intent = new Intent(context, MainService.class);
             intent.setAction(MainService.ACTION_START);
+            intent.putExtra(MainService.EXTRA_LISTEN_INTERFACE, prefs.getString(Constants.PREFS_KEY_SETTINGS_LISTEN_INTERFACE, defaults.getListenInterface()));
             intent.putExtra(MainService.EXTRA_PORT, prefs.getInt(Constants.PREFS_KEY_SETTINGS_PORT, defaults.getPort()));
             intent.putExtra(MainService.EXTRA_PASSWORD, prefs.getString(Constants.PREFS_KEY_SETTINGS_PASSWORD, defaults.getPassword()));
             intent.putExtra(MainService.EXTRA_FILE_TRANSFER, prefs.getBoolean(Constants.PREFS_KEY_SETTINGS_FILE_TRANSFER, defaults.getFileTransfer()));

app/src/main/res/layout/activity_main.xml

@@ -25,6 +25,36 @@
             android:layout_marginBottom="1dp"
             android:padding="10dp">
 
+            <TableRow
+                android:layout_width="match_parent"
+                android:layout_height="match_parent">
+
+                <TextView
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:layout_column="0"
+                    android:padding="10dp"
+                    android:text="@string/main_activity_settings_listening_address" />
+
+                <TextView
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:layout_column="1"
+                    android:padding="10dp"
+                    android:text="@string/main_activity_colon" />
+
+                <EditText
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:layout_column="2"
+                    android:padding="10dp"
+                    android:hint="@string/settings_listen_interface_hint"
+                    android:layout_weight="1"
+                    android:inputType="textUri"
+                    android:maxLines="1"
+                    android:id="@+id/settings_listen_interface"/>
+            </TableRow>
+
             <TableRow
                 android:layout_width="match_parent"
                 android:layout_height="match_parent">

app/src/main/res/values-de/strings.xml

@@ -1,6 +1,7 @@
 <resources>
     <string name="main_activity_title">droidVNC-NG Admin-Panel</string>
     <string name="main_activity_settings">Einstellungen</string>
+    <string name="main_activity_settings_listening_address">Höradresse</string>
     <string name="main_activity_settings_port">Port</string>
     <string name="main_activity_settings_port_not_listening">Eingehende Verbindungen deaktiviert</string>
     <string name="main_activity_settings_password">Passwort</string>

app/src/main/res/values-it/strings.xml

@@ -2,6 +2,7 @@
     <string name="app_name" translatable="false">droidVNC-NG</string>
     <string name="main_activity_title">Amministrazione di droidVNC-NG</string>
     <string name="main_activity_settings">Impostazioni</string>
+    <string name="main_activity_settings_listening_address">Indirizzo d\'ascolto</string>
     <string name="main_activity_settings_port">Porta</string>
     <string name="main_activity_settings_port_not_listening">Connessioni in entrata disabilitate</string>
     <string name="main_activity_settings_password">Password</string>

app/src/main/res/values-ja/strings.xml

@@ -2,6 +2,7 @@
     <string name="app_name" translatable="false">droidVNC-NG</string>
     <string name="main_activity_title">droidVNC-NG管理パネル</string>
     <string name="main_activity_settings">設定</string>
+    <string name="main_activity_settings_listening_address">リスニングアドレス</string>
     <string name="main_activity_settings_port">ポート</string>
     <string name="main_activity_settings_port_not_listening">インバウンド接続は無効です</string>
     <string name="main_activity_settings_password">パスワード</string>